This document discusses limiting work-in-progress (WIP) to improve flow and productivity. It notes that WIP limits prevent bottlenecks from forming by matching team capacity. Both too large and too small of a WIP can create stress, so the optimal range needs to be found for each system. Benefits of limiting WIP include focus, quality, reduced multitasking, and visibility of bottlenecks. There is no magic formula for determining WIP limits; they should be set based on analyzing the system and stress levels, and adjusted over time as the system improves.

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The Art of Limiting WIP
Masa K. Maeda
CEO, Valueinnova LLC USA
@masakmaeda masa@valueinnova.com

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India 2015©Masa K Maeda

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The entire value chain

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WIP
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Stress
WIP limits prevent bottlenecks
from forming by matching the
team’s capacity .
Limiting WIP must consider the
Human Aspect. It isn’t only about
flow but also about sustainability.
Large WIP generates a lot of
stress and so does very small
WIP. Find the range that is right
for your system.

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India 2015©Masa K Maeda
M u l t i t a s k i n g
Because you have the power to be in control

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India 2015©Masa K Maeda
M u l t i t a s k i n g
The art of never being in control

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Multitasking
intensive
is
Time
!

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Ready 6
Design 2 Development 3 Testing 4 UAT 3
Deployment
doing done doing done doing done doing done
Expedite +1

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India 2015©Masa K Maeda
Ready 6
Design 2 Development 3 Testing 4 UAT 3
Deployment
doing done doing done doing done doing done
Expedite 1

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India 2015©Masa K Maeda
๏ Increased cycle time
๏ Increased lead time
๏ More defects
๏ Customer dissatisfaction
๏ Rework
๏ Slow market penetration
๏ Management overhead
๏ Difficulty identifying improvement opportunities
๏ Knowledge degradation (knowledge and info are perishable)
Some
results
from
not
limiting
WIP

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India 2015©Masa K Maeda
Some
benefits
of
limiting
WIP
• Focus on correct decisions
• Task completion
• Quality.
• Reduce multitasking and task switching
• Avoid distraction
• Achieve regular flow to predict delivery
• Measure the real amount of tasks that can be done at a given
time
• Receive feedback to limit waste due to rework and incorrect
assumptions
• Enable a pull model
• Encourage a Done culture
• Make blockers and bottlenecks visible
• Point areas of chronic idleness or overload
• Makes inefficiencies in the system visible

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India 2015©Masa K Maeda
How to determine WIP limits
There’s no magic formula
Don’t make WIP = number of people. If your WIP at some place is the same as the
number of people coincidentally and the actual reason is the result of analysis
then ok
Consider the stress curve and the U-curve optimization
Consider having an upper WIP limit and a lower WIP limit
As your system improves so should your WIPs, as your WIPs improve so will your
system
By changing the WIP you change the system and therefore its behavior. Don’t
change WIPs too frequently or you won’t be able to let the system stabilize and
understand its behavior

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• WIP limits are raised as needed so the team doesn't hit them anymore
• Everyone has a large "background task”
• Team members sit idle waiting for more work to pull in
• No swarming on bottlenecks.
• Throwing more person hours at persistent bottlenecks
Anti-patterns

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Communication
improvement
Here’s some of the improvements our customers have achieved
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Before Month 1 Month 2 Month 3
Builder Co. Designer Co. End Users
Requirements
generation
(days)
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Defect generation
ratio
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Work hrs/week
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Before Month 1
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Before After
Based on the GNH
Projects in danger
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18
27
36
45
Initially Month 2.5
Employee Happiness

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India 2015©Masa K Maeda
masa@valueinnova.com
@masakmaeda